Regenerator or hot-blast stove.



M. SGHROEDER & H. REINHARD.

REGBNEBATOR OR HOT BLAST STOVE.

APPLICATION FILED APB. 30,1912.

1,062,122. v Patented May 20, 1913.

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Hvrkgggk i I mscmonngm'n. EEINHARD. 2 REGENBRATOR 0R HOT BLAST STOVE. 2 APPLICATION rILnnAmmo; 1912.

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Patented May 20, 19 13.

To all whom it may concern-L" 1 UNITED STATES! lPLIENT OFFICE.

MAX SCHROEDER, OF BERLIN, AND ,HUGO REINHARD', 01h OBERHAUSEN, I

" nnen'nnna'ron on. Ho'r' nLAsr scrovnl 'Be it known that we,MAXSoi IRoEDEn;a subj ectof the King of'Priissia, and resident of 41 Klopstockstrasse, Berlin, Germany, and HUGO REINHA D, a' subject of the King of Prussia, and"resident, of; Oberhausen,

Province of the" Rhine, Germany, have jointly invented certain Improvements m aRegenerators or Hot-Blast Stoves; of which the following is a specification.

This invention relatesto improvements in I 'rege'nerators, hot"blastistovesflor thelike.

Hitherto it has been usual to construct the interior brick work-filling ofsuch'apparatlis either in checkered formor so asto pro-p vide vertical flues,-tlie interstices or the flues ofwhich are of a sufficient Width to permit 1 the gases to pass through "the regenerator without being subjected 'to too great a resistance and also to enablethe fiu'e dust to be readily removed, but i the" more regenerators of this type fulfil these conditions, the

less eflicient and complete is the utilization of the waste heat-from the"hotg'ases. In order to utilize the waste heat as efliciently as possible it is therefore necessary to provide an interior brick work having a large surface ;area', thus necessitating the jproa vision of large regenerators,"but it has hithertobeen found, that the efliciency of such regenerators is only about 50% of the total possible efliciency. i As a result thereof the gases leave the regenerator at a high "temperature averaging between 300 and 500? 'C. Not only is'this a great lossbutis at'the: same'time the reason why, by the present apparatuathe highest possible temperatures cannot be attained, as'at each 'stageiof the regenerating action a considerable percentage of heat is lost-{so that the excess heat which is necessaryto" effect a' further increase in the temperature of 'theregener tat-or,"will rapidly cease to exist Moreover it has been hitherto difficult to obtain the proper proportion of gas to air for combustion, so that frequently more than twice the necessary amount of airwassupplied than was necessary for the combustion.

The object of the presentinventionis to obviatethe foregoing disadvantages and for this purpose theinterior of the regenerator is provided with a loosefilling of small pieces of granular" refractory material which are either simplydumped intofthe regenerator'or laid in close layers therein- 3 The size' of'the' pieces may vary fromabou't the size of a henseggfto fabout the sizeiof small, nut or bean. Inasmuch as this fillp I Specificat of et at nt 'iPatentedM ay20Q1913 Application-filed-Apri1 30,1912. serialxasegzoii i ing offers a much greater resistance tothe 'flow ofair andgas'es through the regenerator than heretoforel'usual; it is' necessary to employ forced drsafor this ,purpose; this a beingeifected by means of" compressors,

such as compressors or 'blowers the advan- -blowersor'otherisuitable mechanical means. By the employment of met'zhanicalfmeans tage is also presented' that the combustible gases'and the air forcombustion maybe suitably proportioned, so as to prevent an excess ofg'as' or of air creating "adir'ninu? tion in the temperature caused by 'thelcoma bustio n." Moreover as the air and gases are supplied to the combustion chambers or channels under forced draft a rapid mixture is effected thus dispensing with the neces sity for large combustion chambers hitherto unavoidable; owing to thefact that the air and gases in regenerators of known type,

flow side side without completely mixing 7 with oneanother. p

further advantage of the present construction is that in cases where gastight'fittingssuch as valvesand the like cannot be employed, the air andgasesni'ay bedr'awn through the regenerator under an induced' draft which may bejcreatedby means of exhaust fans or thelike, Such 'ana'rrangement was hitherto impossible, as the 'gases for reheating the regenerator "were atjtooi high a 'temperatiire to enable mechanical draftproducers tobeeinployed, whereas by" thepresent invention thegases before leav- 'ing the regenerator mayfbe. reduced to a v temperatureofbelowa 100C. and even as low as 1 (3.," so that the mechanical draft producing devices employed are not dam} aged thereby.

' It is, already known to se blowers or fans in connection" withhotfblast stoves; but p hitherto such devices havefbeen employed 100' not to overcome'the resistance offered by the stove filling; but to overcome the re" sistance of the blastfurnac'Q5 and {were used only during the heating of the blast whereas the inducing draft of the chimney was employedto draw theairjand gases through the generator during the reheating ther'eofQ is n also known in reverberatory lfurnaces such as p the Martin-furnace,*when used in 'co'njunm tion with a hot blast stove of the Siemens type, to supplyfthe gases-or air under the action of a blower when using cokeioven' or a no blast furnace gases, but in this case also the stove filling ofiers little resistance to the flow of the gases and the latter would be forced into the furnace as soon as the resistance of the stove filling became greater than could be overcome by the inducing ac tion of the chimney, nor can an exhaust fan be substituted for the chimneyfor the reasons hereinbefore .given. It will thus be seen that the employment of a regenerator fillin of great resistance and of a mechanical orced or induced draft are interdependent upon one another.

In order that the invention may bemore clearly understood, reference is made to the accompanying drawings, which show by way of example various methods of carrying out the present invention.

Figurel illustrates in vertical section an arrangement in which only the air blast is heated, this arrangement being particularly adapted where coal gas, coke oven gas,

water gas and the like of high calorific value is employed. As these gases require several times their volume of air for complete combustion, it is unnecessary to heat the gases provided the air for combustion is sufiiciently heated. Fig. 2 illustrates an arrangement in which both the gas and air are heated. This arrangement being applicable'in cases where the gases possess a considerably smaller calorific value, such as generator gases, blast furnace gases and the like. Fig. 3 illustrates an arrange ment applicable for heating the blast of blast furnaces.

Referring to Fig. 1 of the drawings: The apparatus comprises two regenerators a a between which is arranged a reverberatory furnace b. The filling 'v '0 of the furnaces for the regenerators a'a consists of very refractory material such as magnesite or dolomite and where very high temperatures are to be attained, pure burnt lime may be employed. This filling may either rest upon a grating Z of fire-clay or the like, as shown in the regenerators of Fig. 3,- or it may rest upon the conical lower end it of the regenerator, as shown in Fig. 1, the lower part of the filling comprising pieces of larger size, while the upperpart of the filling consists of finer granular material. As the hot combustible gases in the lower part of the regenerator occupy a much greater volume thanthe cool gases passing out: at the upper end of the regenerator, it is preferable to employ a filling whose particles gradually decrease in size from the lower end of the regenerator toward the upper end thereof,

' *inore rapidly and completely,

so as to provide a substantially uniform resistance to theflow of the ases.

As the transference of eat takes place the smaller the particles the size of the latter may be.

so chosen,'that the loss due .to the remainclosed.

ing heat in the waste gases escaping from the regenerator, is reduced to a minimum.

The particles constituting the filling may be either of irregular form or may be of any desired shape laid in close contact with one another.

As the temperature of the regenerator in the upper part thereof is considerably less thanin the lower part thereof, the upper zone of the filling may be of material of less refractoriness, such as fire clay, brick or the like. In cases where the hotgases of combustion pass in a downward direction through' the regenerator, it will of course be understoodthat the filling must be arranged in the opposite manner to that hereinbefore described. p

The operation of the arrangementillustrated in Fig. 1 is as follows :The gases for combustion in a cold state are supplied by a compressor, blower or other suitable device a to the regenerator at the necessary pressure in order to overcome the resistance offered by the filling o 0 These mechanical devices may also be adapted to enable the quantity supplied thereby to be determined in any known manner. The gas from the compressor "0 is supplied to the pipes e e which are provided with suitable valves 27 M respectively, so that the gas cam be alternately supplied to the regenerators a a respectively. The air for combustion is supplied in like manner under pressure by means of'compressors or suitable mechanicombustion is first of all supplied by way of the pi e f, while the valves 0 u n are The air traverses the regenerator a in a downward direction and meets the ases entering by way of the pipe e in the c annel d" where the mixture is ignited and passesthroughthe furnace 6 into the channel d in the regenerator 111 in which it gives up, its heat to the filling o ator and-escapes byway of the exit pipe 9 in said regener- After the lower part of the filling '0 in the regenerator. a has been raised to a glow, the

respectively and anexhauster m. The air for gas current is reversed by closing the valves l t, m, and p and opening the valves u, n, 0. As the combustion now takes place with preheated air, the temperature in the furnace b will be raised and the lower part of the filling 'v in the regenerator araised to a higher temperature than the filling 12 was raised. On again reversing the direction of the gas current a further increase in the temperature will take place, as the air will be raised to a higher temperature at each reversal of the operation, until the furnace b absorbs as much heat as is supplied by the verse direction through tor gases,

combustion. If theffurnace chamber?) is of comparatively small dimension andbe only used for such processes as require relatively small quantities ofheat, very high tempera.- tures can be attained by this arrangement in spite of theuse of cold furnace gases.

The increase in temperature may be accelerated andstill further increased if both the gas and air are previously heated. In this'case gases may be employed of consid erably lower calorific value, such as genera blast furnace gases and the like. The method in this case corresponds somewhat to the Siemens type of regenerator but differs therefrom in the type .of filling and in the employment of mechanical means for passing the as therethrough. An arrangement suitaEle for carrying out this method isillustrated in Fig. 2. -The regenerators at a serve in like manner as -in Fig. 1 for alternately heating the'air for combustion, while additional regenerators (l -a are provided for heatin thefurnace gases. The pipes e e serve or the admission of the furnace gases being connected to a blower or the like 0 and the pipes f ji serve for. the admission of air being connected to a blower or the'like w. The exit for the gases of combustion takes place on one hand through the exit pipes g and g? and in' the reverse direction through'the exit pipes g? g respectively, provided with the valves 0, p, g andr. respectively and a common exhauster m. In operation the air and gases are supplied inthe usual manner, firstly through the pipes e .f while the pipes g and g are closedby means of the valves 0 and g respectively and in the rethe pipes e andy, while the pipes g g are closed by means of the valves p and a respectively.

In cases where the regenerator is-to be employed as a hot blast stove for heating the air blast of blast furnaces and thelike, the arrangement illustrated in Fig. 3 maybe employed, which differs only from Fig. 1 in that the regenerators a a are connected by means of a pipe 8, which is provided with a lateral hot air outlet 6 connected to the hot blast furnace y and in connection with a manometer k for the purpose hereinafter set forth. In order to enable part of the hotair to be supplied to. the blast furnace through the connection 1', the air mix with the furnace gases after having passed through the connecting'pipe s and for this purpose, when air is supplied by way of the blower 10 furnace gases are supplied by way of the "blower c and the pipe e instead of the pipe The combustion thentakes place in thea. lower channel (i of the regenerator a, the products of combustion rising through the regenerator a and giving up' their heat to 'thefilling 'v and escaping by way of the furnace gases.

it is necessary that and the pipe f, the

outlet pipe g. Thepassage oftheair and gas therefore takes place during one. phase in the dlrection of the arrows in Fig. 3.

When' the gas current is reversed, the valves closed and the valves m, p and u opened. As the heat of the products of combustion in this case is not absorbed, as in Figs. 1 and 2, an increase in temperature will take place on each reversal of the current .through the'apparatus, until the upper part of the filling in the regenerators n,- tand 0 are heat. As soon as this takes place, the regenerator is then ready for use. The readingof the manometer 7c is then taken in order to ascertain what pressure is necessary to force the combustible gases through the apparatus. In order now to utilize the additional quantities of heat on furthercombustion in the apparatus, it is necessary to considerably increase the current of air alternately blown into .the apparatus by the blower w? through the valves m and 'n,

is so hot that it is unable to absorb more so that a greater quantity of air is supplied than is necessary for the combustion of the Assoon as this greater quantity of air'is supplied, the friction and resistancein the filling is increased and in consequence thereof the pressure registered by the manometer 70 will be raised. If now hot air is conducted away. through the connection iso that the pressure is reducedto its previous state, the quantity of air removed will correspond exactly tothe air in excess of that necessary for combustion.

Inasmuch as the connection 71 leads to the blast furnace, it is thus possible to supply a uniform hot blast to the furnace independently of the direction of the flow of the gasesthrough the regenerator. The amount of air drawn off through the connection 2' may "be regulated by inserting suitable re-. sistances in front of or behind the blast furnace, so that the required pressure is maintained in the apparatus. Furthermore the size of the regenerators may be so chosen, that the resistance therein equalizes the resistance present in the blast furnace, slight variation being capable of compensation by varying the drive for the compressors or the like 0 w? according to the pressure registered by the manometer is. It will of course also be understood that the supply of air to the blast furnace canbe accurately regulated by ascertaining the quantity of waste gases exiting from the blast furnace and cal- ;ulating the quantity of air necessary there- As a general rule the excess quantity of air supplied to the regenerators must be sufiicient to absorb the heat generated at each combustion, this quantitynot being dependa case the waste raised, while the quantity of excess air can that the apin Fig. 3 may be emmanner for obtaining a current of heated combustible gas for the purpose of reduction at high temperatures,-

the combustible gas being admitted in this case by wayof the blower-w and the pipes j f and the air being admitted by way of the blower c and pipes e 6 in which case an excess quantity of combustible gas will be supplied to the regenerators and conducted away through the connection 2' to the reducing furnace in a similar manner to that already described.

If the arrangement illustrated in Fig. 3 is duplicated so that one of the apparatus supplies a heated current of air and the other a heated current of combustible gases, the apparatus may then be employed in conjunction with a reverberatory furnace, at the same time enabling combustible gases of low calorific value to be employed. In this gases will not be returned to the regenerator thus particularly adapting the apparatus to sublimation and other chemical processes, in which the volatile component escapes with the combustible gases and is subsequently separated therefrom by cooling.

e claim,

1. In a regenerator, hot blast stove or the like, a compact filling of granular refractory material consisting of pieces of such a size that the total resistance offered thereby to the flow of gases therethrough is such as to require the gases to be forced through the said filling by mechanical means other than the draft of a chimney.

2. In a regenerator, hot blast stove or the like, a filling of granularref'ractory material, the size of the particles decreasing from the lower to the upper end of said filling, and mechanical means for forcing the gases therethrough.

3. In combination with a furnace, a regenerator tower on each side thereof, a compact filling of granular refractory material in each of said towers consisting of pieces of small size, a connection between said towers, a branch pipe from said connection to said furnace, mechanical means for supplying under pressure air to the one tower and combustible gas to the other tower first in one direction and then in the opposite direction alternately, after passing through the one tower into said connection is divided, one part thereof passing to the furnace and the other part thereof passing into the other tower and being used for creating combustion in the latter.

In witness whereof we have hereunto set our hands in the presence of witnesses.

MAX SCHROEDER. HUGO REINHARD.

whereby the air or gas 

